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Women who suffer from autoimmune disorders
such as rheumatoid arthritis and multiple sclerosis may find
relief during pregnancy but their symptoms may become even
worse after they give birth.
Increased levels of certain stress
hormones during the final trimester of pregnancy may suppress
immune system proteins involved in inflammation, a hallmark
of autoimmune disorders.
But in
the weeks after pregnancy, levels of these hormones fall sharply,
resulting in higher levels of inflammatory proteins that may
contribute to arthritis and multiple sclerosis.
Multiple sclerosis occurs when the body's
immune system attacks the central nervous system and destroys
myelin, the protective coating that insulates nerve fibers
in the brain and spine.
The destruction of myelin can lead to
numbness, muscle weakness and stiffness. In rheumatoid arthritis,
the immune system attacks the lining of the joints, causing
pain, stiffness and inflammation. There is no traditional
medical cure for either disease.
Levels of interleukin-12 (IL-12) were
about three times lower in the final trimester of pregnancy
compared with levels measured after birth. Similarly, levels
of tumor necrosis factor (TNF)-alpha were about 40%
lower during the third trimester.
IL-12 and TNF-alpha are proteins that
trigger the body's immune system to fight disease but are
also involved in the swelling and tissue destruction that
marks autoimmune disorders.
Meantime, levels of cortisol, norepinephrine
and 1,25-dihydroxyvitamin were higher in the third trimester
compared with levels measured after birth. Previous studies
have shown that these hormones can suppress levels of IL-12
and TNF-alpha.
Journal
of Clinical Endocrinology and Metabolism October 2001;86:4933-4938
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